My post last week involved the replacement of the rear brake lines. Now, with the system bled, the pedal is very soft and the brakes do not "grab" until the pedal is 3/4 of the way to the floor [note: the brakes do work, just do not feel like they did before the lines burst].

My thought (well, some other people also) is that the master cylinder was damaged when I pushed the brake pedal and forced all the fluid out of the system, that the plunger in the master cylinder was pushed to far and the seals were damaged.

Has anyone else experienced this? I would like to rebuild the master cylinder verses buying a new one and I found some previous posts about rebuilding the master cylinder. I checked at Advance Auto and they do not list any MC rebuild kits.

Where do I get a rebuild kit? Opinions on if this will fix my soft brake pedal? One more question-- the FSM does not mention bench bleeding the master cylinder when replacing. Is bench bleeding necessary?

Thanks in advance,
Scott

 

save yourself time, money and problems. Buy a new master cylinder. Bench bleeding will save you a TON of work. If you bench bleed the MC you will take all the air out of it so you won't need to make sure you got all the air out of the lines. After you bench bleed it and install it, have someone help you and crack the lines at the mc just to get any residual out there and then just to cover your bases, rebleed your lines starting with the wheel farthest from the mc

 

yep same thing happened here rear line on the rear axle popped and all hell broke out everything from the pedal to the wheels got replaced

 

If you have a good hard pedal, just too far down, try tightening your rear brakes before doing anything else. If you don't know how to do that... do a quick search on it... we have tons of threads here on adjusting your rear brakes. That is the most common problem with the low pedal symptom.